diff --git a/ROMFS/px4fmu_common/init.d/31_io_phantom b/ROMFS/px4fmu_common/init.d/31_io_phantom
index 63cd7f9b2e..62cfe1a9c6 100644
--- a/ROMFS/px4fmu_common/init.d/31_io_phantom
+++ b/ROMFS/px4fmu_common/init.d/31_io_phantom
@@ -8,30 +8,35 @@ echo "[init] PX4FMU v1, v2 with or without IO on Phantom FPV"
 if param compare SYS_AUTOCONFIG 1
 then
 	# Set all params here, then disable autoconfig
+	param set FW_AIRSPD_MIN 11.4
+	param set FW_AIRSPD_TRIM 14
+	param set FW_AIRSPD_MAX 22
+	param set FW_L1_PERIOD 15
 	param set FW_P_D 0
 	param set FW_P_I 0
 	param set FW_P_IMAX 15
-	param set FW_P_LIM_MAX 50
-	param set FW_P_LIM_MIN -50
+	param set FW_P_LIM_MAX 45
+	param set FW_P_LIM_MIN -45
 	param set FW_P_P 60
 	param set FW_P_RMAX_NEG 0
 	param set FW_P_RMAX_POS 0
-	param set FW_P_ROLLFF 1.1
+	param set FW_P_ROLLFF 2
 	param set FW_R_D 0
 	param set FW_R_I 5
-	param set FW_R_IMAX 20
-	param set FW_R_P 100
-	param set FW_R_RMAX 100
-	param set FW_THR_CRUISE 0.65
+	param set FW_R_IMAX 15
+	param set FW_R_P 80
+	param set FW_R_RMAX 60
+	param set FW_THR_CRUISE 0.8
+	param set FW_THR_LND_MAX 0
 	param set FW_THR_MAX 1
-	param set FW_THR_MIN 0
+	param set FW_THR_MIN 0.5
 	param set FW_T_SINK_MAX 5.0
-	param set FW_T_SINK_MIN 4.0
-	param set FW_Y_ROLLFF 1.1
-	param set FW_L1_PERIOD 17
-	param set RC_SCALE_ROLL 1.0
-	param set RC_SCALE_PITCH 1.0
-	
+	param set FW_T_SINK_MIN 2.0
+	param set FW_Y_ROLLFF 1.0
+	param set RC_SCALE_ROLL 0.6
+	param set RC_SCALE_PITCH 0.6
+	param set TRIM_PITCH 0.1
+
 	param set SYS_AUTOCONFIG 0
 	param save
 fi
diff --git a/ROMFS/px4fmu_common/init.d/33_io_wingwing b/ROMFS/px4fmu_common/init.d/33_io_wingwing
new file mode 100644
index 0000000000..538c69711d
--- /dev/null
+++ b/ROMFS/px4fmu_common/init.d/33_io_wingwing
@@ -0,0 +1,91 @@
+#!nsh
+
+echo "[init] PX4FMU v1, v2 with or without IO on the Wing Wing (aka Z-84)"
+
+#
+# Load default params for this platform
+#
+if param compare SYS_AUTOCONFIG 1
+then
+   # Set all params here, then disable autoconfig
+   param set FW_AIRSPD_MIN 7
+   param set FW_AIRSPD_TRIM 9
+   param set FW_AIRSPD_MAX 14
+   param set FW_L1_PERIOD 10
+   param set FW_P_D 0
+   param set FW_P_I 0
+   param set FW_P_IMAX 20
+   param set FW_P_LIM_MAX 30
+   param set FW_P_LIM_MIN -20
+   param set FW_P_P 30
+   param set FW_P_RMAX_NEG 0
+   param set FW_P_RMAX_POS 0
+   param set FW_P_ROLLFF 2
+   param set FW_R_D 0
+   param set FW_R_I 5
+   param set FW_R_IMAX 20
+   param set FW_R_P 60
+   param set FW_R_RMAX 60
+   param set FW_THR_CRUISE 0.65
+   param set FW_THR_MAX 0.7
+   param set FW_THR_MIN 0
+   param set FW_T_SINK_MAX 5
+   param set FW_T_SINK_MIN 2
+   param set FW_T_TIME_CONST 9
+   param set FW_Y_ROLLFF 2.0
+   param set RC_SCALE_ROLL 1.0
+   param set RC_SCALE_PITCH 1.0
+
+   param set SYS_AUTOCONFIG 0
+   param save
+fi
+ 
+#
+# Force some key parameters to sane values
+# MAV_TYPE     1 = fixed wing
+#
+param set MAV_TYPE 1
+
+set EXIT_ON_END no
+
+#
+# Start and configure PX4IO or FMU interface
+#
+if px4io detect
+then
+   # Start MAVLink (depends on orb)
+   mavlink start
+
+   sh /etc/init.d/rc.io
+   # Limit to 100 Hz updates and (implicit) 50 Hz PWM
+   px4io limit 100
+else
+   # Start MAVLink (on UART1 / ttyS0)
+   mavlink start -d /dev/ttyS0
+
+   fmu mode_pwm
+   param set BAT_V_SCALING 0.004593
+   set EXIT_ON_END yes
+fi
+
+#
+# Load mixer and start controllers (depends on px4io)
+#
+if [ -f /fs/microsd/etc/mixers/FMU_Q.mix ]
+then
+   echo "Using /fs/microsd/etc/mixers/FMU_Q.mix"
+   mixer load /dev/pwm_output /fs/microsd/etc/mixers/FMU_Q.mix
+else
+   echo "Using /etc/mixers/FMU_Q.mix"
+   mixer load /dev/pwm_output /etc/mixers/FMU_Q.mix
+fi
+
+#
+# Start common fixedwing apps
+#
+sh /etc/init.d/rc.fixedwing
+
+if [ $EXIT_ON_END == yes ]
+then
+   exit
+fi
\ No newline at end of file
diff --git a/ROMFS/px4fmu_common/init.d/34_io_fx79 b/ROMFS/px4fmu_common/init.d/34_io_fx79
new file mode 100644
index 0000000000..9892049526
--- /dev/null
+++ b/ROMFS/px4fmu_common/init.d/34_io_fx79
@@ -0,0 +1,91 @@
+#!nsh
+
+echo "[init] PX4FMU v1, v2 with or without IO on FX-79 Buffalo"
+
+#
+# Load default params for this platform
+#
+if param compare SYS_AUTOCONFIG 1
+then
+	# Set all params here, then disable autoconfig
+	param set FW_AIRSPD_MAX 20
+	param set FW_AIRSPD_TRIM 12
+	param set FW_AIRSPD_MIN 15
+	param set FW_L1_PERIOD 12
+	param set FW_P_D 0
+	param set FW_P_I 0
+	param set FW_P_IMAX 15
+	param set FW_P_LIM_MAX 50
+	param set FW_P_LIM_MIN -50
+	param set FW_P_P 60
+	param set FW_P_RMAX_NEG 0
+	param set FW_P_RMAX_POS 0
+	param set FW_P_ROLLFF 1.1
+	param set FW_R_D 0
+	param set FW_R_I 5
+	param set FW_R_IMAX 20
+	param set FW_R_P 80
+	param set FW_R_RMAX 100
+	param set FW_THR_CRUISE 0.75
+	param set FW_THR_MAX 1
+	param set FW_THR_MIN 0
+	param set FW_T_SINK_MAX 5.0
+	param set FW_T_SINK_MIN 4.0
+	param set FW_T_TIME_CONST 9
+	param set FW_Y_ROLLFF 1.1	
+	param set RC_SCALE_ROLL 1.0
+	param set RC_SCALE_PITCH 1.0
+	
+	param set SYS_AUTOCONFIG 0
+	param save
+fi
+ 
+#
+# Force some key parameters to sane values
+# MAV_TYPE     1 = fixed wing
+#
+param set MAV_TYPE 1
+
+set EXIT_ON_END no
+
+#
+# Start and configure PX4IO or FMU interface
+#
+if px4io detect
+then
+	# Start MAVLink (depends on orb)
+	mavlink start
+
+	sh /etc/init.d/rc.io
+	# Limit to 100 Hz updates and (implicit) 50 Hz PWM
+	px4io limit 100
+else
+	# Start MAVLink (on UART1 / ttyS0)
+	mavlink start -d /dev/ttyS0
+
+	fmu mode_pwm
+	param set BAT_V_SCALING 0.004593
+	set EXIT_ON_END yes
+fi
+
+#
+# Load mixer and start controllers (depends on px4io)
+#
+if [ -f /fs/microsd/etc/mixers/FMU_FX79.mix ]
+then
+	echo "Using /fs/microsd/etc/mixers/FMU_FX79.mix"
+	mixer load /dev/pwm_output /fs/microsd/etc/mixers/FMU_FX79.mix
+else
+	echo "Using /etc/mixers/FMU_FX79.mix"
+	mixer load /dev/pwm_output /etc/mixers/FMU_FX79.mix
+fi
+
+#
+# Start common fixedwing apps
+#
+sh /etc/init.d/rc.fixedwing
+
+if [ $EXIT_ON_END == yes ]
+then
+	exit
+fi
diff --git a/ROMFS/px4fmu_common/init.d/800_sdlogger b/ROMFS/px4fmu_common/init.d/800_sdlogger
new file mode 100644
index 0000000000..955fe0e2ad
--- /dev/null
+++ b/ROMFS/px4fmu_common/init.d/800_sdlogger
@@ -0,0 +1,60 @@
+#!nsh
+
+echo "[init] PX4FMU v1, v2 init to log only
+
+#
+# Load default params for this platform
+#
+if param compare SYS_AUTOCONFIG 1
+then
+	# Set all params here, then disable autoconfig
+	param set SYS_AUTOCONFIG 0
+	
+	param save
+fi
+
+set EXIT_ON_END no
+
+#
+# Start and configure PX4IO or FMU interface
+#
+if px4io detect
+then
+	# Start MAVLink (depends on orb)
+	mavlink start
+	usleep 5000
+
+	commander start
+
+	sh /etc/init.d/rc.io
+	# Set PWM values for DJI ESCs
+else
+	# Start MAVLink (on UART1 / ttyS0)
+	mavlink start -d /dev/ttyS0
+	usleep 5000
+	param set BAT_V_SCALING 0.004593
+	set EXIT_ON_END yes
+fi
+
+sh /etc/init.d/rc.sensors
+
+gps start
+
+attitude_estimator_ekf start
+
+position_estimator_inav start
+
+if [ -d /fs/microsd ]
+then
+	if [ $BOARD == fmuv1 ]
+	then
+		sdlog2 start -r 50 -e -b 16
+	else
+		sdlog2 start -r 200 -e -b 16
+	fi
+fi
+
+if [ $EXIT_ON_END == yes ]
+then
+	exit
+fi
diff --git a/ROMFS/px4fmu_common/init.d/rcS b/ROMFS/px4fmu_common/init.d/rcS
index 14bb820fa9..6eac00d0c6 100644
--- a/ROMFS/px4fmu_common/init.d/rcS
+++ b/ROMFS/px4fmu_common/init.d/rcS
@@ -331,6 +331,18 @@ then
 		set MODE custom
 	fi
 
+	if param compare SYS_AUTOSTART 33
+	then
+		sh /etc/init.d/33_io_wingwing
+		set MODE custom
+	fi
+
+        if param compare SYS_AUTOSTART 34
+        then
+                sh /etc/init.d/34_io_fx79
+                set MODE custom
+        fi
+
 	if param compare SYS_AUTOSTART 40
 	then
 		sh /etc/init.d/40_io_segway
@@ -355,6 +367,12 @@ then
 		set MODE custom
 	fi
 	
+	if param compare SYS_AUTOSTART 800
+	then
+		sh /etc/init.d/800_sdlogger
+		set MODE custom
+	fi
+	
 	# Start any custom extensions that might be missing
 	if [ -f /fs/microsd/etc/rc.local ]
 	then
diff --git a/ROMFS/px4fmu_common/mixers/FMU_FX79.mix b/ROMFS/px4fmu_common/mixers/FMU_FX79.mix
new file mode 100755
index 0000000000..0a1dca98d5
--- /dev/null
+++ b/ROMFS/px4fmu_common/mixers/FMU_FX79.mix
@@ -0,0 +1,72 @@
+FX-79 Delta-wing mixer for PX4FMU
+=================================
+
+Designed for FX-79.
+
+TODO (sjwilks): Add mixers for flaps.
+
+This file defines mixers suitable for controlling a delta wing aircraft using
+PX4FMU. The configuration assumes the elevon servos are connected to PX4FMU
+servo outputs 0 and 1 and the motor speed control to output 3. Output 2 is
+assumed to be unused.
+
+Inputs to the mixer come from channel group 0 (vehicle attitude), channels 0
+(roll), 1 (pitch) and 3 (thrust).
+
+See the README for more information on the scaler format.
+
+Elevon mixers
+-------------
+Three scalers total (output, roll, pitch).
+
+On the assumption that the two elevon servos are physically reversed, the pitch
+input is inverted between the two servos.
+
+The scaling factor for roll inputs is adjusted to implement differential travel
+for the elevons.
+
+M: 2
+O:      10000  10000      0 -10000  10000
+S: 0 0   5000   8000      0 -10000  10000
+S: 0 1   8000   8000      0 -10000  10000
+
+M: 2
+O:      10000  10000      0 -10000  10000
+S: 0 0   8000   5000      0 -10000  10000
+S: 0 1  -8000  -8000      0 -10000  10000
+
+Output 2
+--------
+This mixer is empty.
+
+Z:
+
+Motor speed mixer
+-----------------
+Two scalers total (output, thrust).
+
+This mixer generates a full-range output (-1 to 1) from an input in the (0 - 1)
+range.  Inputs below zero are treated as zero.
+
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 3      0  20000 -10000 -10000  10000
+
+Gimbal / flaps / payload mixer for last four channels
+-----------------------------------------------------
+
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 4  10000  10000      0 -10000  10000
+
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 5  10000  10000      0 -10000  10000
+
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 6  10000  10000      0 -10000  10000
+
+M: 1
+O:      10000  10000      0 -10000  10000
+S: 0 7  10000  10000      0 -10000  10000
diff --git a/src/drivers/drv_rc_input.h b/src/drivers/drv_rc_input.h
index 6f773b82a8..03f1dfbe58 100644
--- a/src/drivers/drv_rc_input.h
+++ b/src/drivers/drv_rc_input.h
@@ -89,7 +89,7 @@ struct rc_input_values {
 	/** number of channels actually being seen */
 	uint32_t		channel_count;
 
-	/** receive signal strength indicator (RSSI): < 0: Undefined, 0: no signal, 1000: full reception */
+	/** receive signal strength indicator (RSSI): < 0: Undefined, 0: no signal, 255: full reception */
 	int32_t			rssi;
 
 	/** Input source */
diff --git a/src/drivers/px4io/px4io.cpp b/src/drivers/px4io/px4io.cpp
index 4e9daf9106..cbdd5acc44 100644
--- a/src/drivers/px4io/px4io.cpp
+++ b/src/drivers/px4io/px4io.cpp
@@ -850,7 +850,7 @@ PX4IO::task_main()
 
 			/* we're not nice to the lower-priority control groups and only check them
 			   when the primary group updated (which is now). */
-			io_set_control_groups();
+			(void)io_set_control_groups();
 		}
 
 		if (now >= poll_last + IO_POLL_INTERVAL) {
@@ -962,14 +962,14 @@ out:
 int
 PX4IO::io_set_control_groups()
 {
-	bool attitude_ok = io_set_control_state(0);
+	int ret = io_set_control_state(0);
 
 	/* send auxiliary control groups */
 	(void)io_set_control_state(1);
 	(void)io_set_control_state(2);
 	(void)io_set_control_state(3);
 
-	return attitude_ok;
+	return ret;
 }
 
 int
@@ -1095,8 +1095,10 @@ PX4IO::io_set_rc_config()
 	 * assign RC_MAP_ROLL/PITCH/YAW/THROTTLE to the canonical
 	 * controls.
 	 */
+
+	/* fill the mapping with an error condition triggering value */
 	for (unsigned i = 0; i < _max_rc_input; i++)
-		input_map[i] = -1;
+		input_map[i] = UINT8_MAX;
 
 	/*
 	 * NOTE: The indices for mapped channels are 1-based
@@ -1128,12 +1130,6 @@ PX4IO::io_set_rc_config()
 	if ((ichan >= 0) && (ichan < (int)_max_rc_input))
 		input_map[ichan - 1] = 4;
 
-	ichan = 5;
-
-	for (unsigned i = 0; i < _max_rc_input; i++)
-		if (input_map[i] == -1)
-			input_map[i] = ichan++;
-
 	/*
 	 * Iterate all possible RC inputs.
 	 */
@@ -1801,6 +1797,16 @@ PX4IO::print_status()
 		printf(" %u", io_reg_get(PX4IO_PAGE_RAW_RC_INPUT, PX4IO_P_RAW_RC_BASE + i));
 
 	printf("\n");
+
+	if (raw_inputs > 0) {
+		int frame_len = io_reg_get(PX4IO_PAGE_STATUS, PX4IO_P_STATUS_RC_DATA);
+		printf("RC data (PPM frame len) %u us\n", frame_len);
+
+		if ((frame_len - raw_inputs * 2000 - 3000) < 0) {
+			printf("WARNING  WARNING  WARNING! This RC receiver does not allow safe frame detection.\n");
+		}
+	}
+
 	uint16_t mapped_inputs = io_reg_get(PX4IO_PAGE_RC_INPUT, PX4IO_P_RC_VALID);
 	printf("mapped R/C inputs 0x%04x", mapped_inputs);
 
diff --git a/src/drivers/stm32/drv_hrt.c b/src/drivers/stm32/drv_hrt.c
index f105251f0a..b7c9b89a45 100644
--- a/src/drivers/stm32/drv_hrt.c
+++ b/src/drivers/stm32/drv_hrt.c
@@ -1,6 +1,6 @@
 /****************************************************************************
  *
- *   Copyright (C) 2012 PX4 Development Team. All rights reserved.
+ *   Copyright (c) 2012, 2013 PX4 Development Team. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -168,7 +168,7 @@
 # error HRT_TIMER_CLOCK must be greater than 1MHz
 #endif
 
-/*
+/**
  * Minimum/maximum deadlines.
  *
  * These are suitable for use with a 16-bit timer/counter clocked
@@ -276,12 +276,16 @@ static void		hrt_call_invoke(void);
  * Specific registers and bits used by PPM sub-functions
  */
 #ifdef HRT_PPM_CHANNEL
-/* 
+/*
  * If the timer hardware doesn't support GTIM_CCER_CCxNP, then we will work around it.
  *
  * Note that we assume that M3 means STM32F1 (since we don't really care about the F2).
  */
 # ifdef CONFIG_ARCH_CORTEXM3
+#  undef GTIM_CCER_CC1NP
+#  undef GTIM_CCER_CC2NP
+#  undef GTIM_CCER_CC3NP
+#  undef GTIM_CCER_CC4NP
 #  define GTIM_CCER_CC1NP 0
 #  define GTIM_CCER_CC2NP 0
 #  define GTIM_CCER_CC3NP 0
@@ -332,19 +336,21 @@ static void		hrt_call_invoke(void);
 /*
  * PPM decoder tuning parameters
  */
-# define PPM_MAX_PULSE_WIDTH	550		/* maximum width of a valid pulse */
-# define PPM_MIN_CHANNEL_VALUE	800		/* shortest valid channel signal */
-# define PPM_MAX_CHANNEL_VALUE	2200		/* longest valid channel signal */
-# define PPM_MIN_START		2500		/* shortest valid start gap */
+# define PPM_MIN_PULSE_WIDTH	200		/**< minimum width of a valid first pulse */
+# define PPM_MAX_PULSE_WIDTH	600		/**< maximum width of a valid first pulse */
+# define PPM_MIN_CHANNEL_VALUE	800		/**< shortest valid channel signal */
+# define PPM_MAX_CHANNEL_VALUE	2200		/**< longest valid channel signal */
+# define PPM_MIN_START		2300		/**< shortest valid start gap (only 2nd part of pulse) */
 
 /* decoded PPM buffer */
 #define PPM_MIN_CHANNELS	5
 #define PPM_MAX_CHANNELS	20
 
-/* Number of same-sized frames required to 'lock' */
-#define PPM_CHANNEL_LOCK	4		/* should be less than the input timeout */
+/** Number of same-sized frames required to 'lock' */
+#define PPM_CHANNEL_LOCK	4		/**< should be less than the input timeout */
 
 __EXPORT uint16_t ppm_buffer[PPM_MAX_CHANNELS];
+__EXPORT uint16_t ppm_frame_length = 0;
 __EXPORT unsigned ppm_decoded_channels = 0;
 __EXPORT uint64_t ppm_last_valid_decode = 0;
 
@@ -358,11 +364,12 @@ unsigned ppm_pulse_next;
 
 static uint16_t ppm_temp_buffer[PPM_MAX_CHANNELS];
 
-/* PPM decoder state machine */
+/** PPM decoder state machine */
 struct {
-	uint16_t	last_edge;	/* last capture time */
-	uint16_t	last_mark;	/* last significant edge */
-	unsigned	next_channel;
+	uint16_t	last_edge;	/**< last capture time */
+	uint16_t	last_mark;	/**< last significant edge */
+	uint16_t	frame_start;	/**< the frame width */
+	unsigned	next_channel;	/**< next channel index */
 	enum {
 		UNSYNCH = 0,
 		ARM,
@@ -384,7 +391,7 @@ static void	hrt_ppm_decode(uint32_t status);
 # define CCER_PPM	0
 #endif /* HRT_PPM_CHANNEL */
 
-/*
+/**
  * Initialise the timer we are going to use.
  *
  * We expect that we'll own one of the reduced-function STM32 general
@@ -430,7 +437,7 @@ hrt_tim_init(void)
 }
 
 #ifdef HRT_PPM_CHANNEL
-/*
+/**
  * Handle the PPM decoder state machine.
  */
 static void
@@ -447,7 +454,6 @@ hrt_ppm_decode(uint32_t status)
 
 	/* how long since the last edge? - this handles counter wrapping implicitely. */
 	width = count - ppm.last_edge;
-	ppm.last_edge = count;
 
 	ppm_edge_history[ppm_edge_next++] = width;
 
@@ -491,6 +497,7 @@ hrt_ppm_decode(uint32_t status)
 					ppm_buffer[i] = ppm_temp_buffer[i];
 
 				ppm_last_valid_decode = hrt_absolute_time();
+
 			}
 		}
 
@@ -500,29 +507,39 @@ hrt_ppm_decode(uint32_t status)
 		/* next edge is the reference for the first channel */
 		ppm.phase = ARM;
 
+		ppm.last_edge = count;
 		return;
 	}
 
 	switch (ppm.phase) {
 	case UNSYNCH:
 		/* we are waiting for a start pulse - nothing useful to do here */
-		return;
+		break;
 
 	case ARM:
 
 		/* we expect a pulse giving us the first mark */
-		if (width > PPM_MAX_PULSE_WIDTH)
-			goto error;		/* pulse was too long */
+		if (width < PPM_MIN_PULSE_WIDTH || width > PPM_MAX_PULSE_WIDTH)
+			goto error;		/* pulse was too short or too long */
 
 		/* record the mark timing, expect an inactive edge */
-		ppm.last_mark = count;
-		ppm.phase = INACTIVE;
-		return;
+		ppm.last_mark = ppm.last_edge;
+
+		/* frame length is everything including the start gap */
+		ppm_frame_length = (uint16_t)(ppm.last_edge - ppm.frame_start);
+		ppm.frame_start = ppm.last_edge;
+		ppm.phase = ACTIVE;
+		break;
 
 	case INACTIVE:
+
+		/* we expect a short pulse */
+		if (width < PPM_MIN_PULSE_WIDTH || width > PPM_MAX_PULSE_WIDTH)
+			goto error;		/* pulse was too short or too long */
+
 		/* this edge is not interesting, but now we are ready for the next mark */
 		ppm.phase = ACTIVE;
-		return;
+		break;
 
 	case ACTIVE:
 		/* determine the interval from the last mark */
@@ -543,10 +560,13 @@ hrt_ppm_decode(uint32_t status)
 			ppm_temp_buffer[ppm.next_channel++] = interval;
 
 		ppm.phase = INACTIVE;
-		return;
+		break;
 
 	}
 
+	ppm.last_edge = count;
+	return;
+
 	/* the state machine is corrupted; reset it */
 
 error:
@@ -557,7 +577,7 @@ error:
 }
 #endif /* HRT_PPM_CHANNEL */
 
-/*
+/**
  * Handle the compare interupt by calling the callout dispatcher
  * and then re-scheduling the next deadline.
  */
@@ -586,6 +606,7 @@ hrt_tim_isr(int irq, void *context)
 
 		hrt_ppm_decode(status);
 	}
+
 #endif
 
 	/* was this a timer tick? */
@@ -604,7 +625,7 @@ hrt_tim_isr(int irq, void *context)
 	return OK;
 }
 
-/*
+/**
  * Fetch a never-wrapping absolute time value in microseconds from
  * some arbitrary epoch shortly after system start.
  */
@@ -651,7 +672,7 @@ hrt_absolute_time(void)
 	return abstime;
 }
 
-/*
+/**
  * Convert a timespec to absolute time
  */
 hrt_abstime
@@ -665,7 +686,7 @@ ts_to_abstime(struct timespec *ts)
 	return result;
 }
 
-/*
+/**
  * Convert absolute time to a timespec.
  */
 void
@@ -676,7 +697,7 @@ abstime_to_ts(struct timespec *ts, hrt_abstime abstime)
 	ts->tv_nsec = abstime * 1000;
 }
 
-/*
+/**
  * Compare a time value with the current time.
  */
 hrt_abstime
@@ -691,7 +712,7 @@ hrt_elapsed_time(const volatile hrt_abstime *then)
 	return delta;
 }
 
-/*
+/**
  * Store the absolute time in an interrupt-safe fashion
  */
 hrt_abstime
@@ -706,7 +727,7 @@ hrt_store_absolute_time(volatile hrt_abstime *now)
 	return ts;
 }
 
-/*
+/**
  * Initalise the high-resolution timing module.
  */
 void
@@ -721,7 +742,7 @@ hrt_init(void)
 #endif
 }
 
-/*
+/**
  * Call callout(arg) after interval has elapsed.
  */
 void
@@ -734,7 +755,7 @@ hrt_call_after(struct hrt_call *entry, hrt_abstime delay, hrt_callout callout, v
 			  arg);
 }
 
-/*
+/**
  * Call callout(arg) at calltime.
  */
 void
@@ -743,7 +764,7 @@ hrt_call_at(struct hrt_call *entry, hrt_abstime calltime, hrt_callout callout, v
 	hrt_call_internal(entry, calltime, 0, callout, arg);
 }
 
-/*
+/**
  * Call callout(arg) every period.
  */
 void
@@ -762,13 +783,13 @@ hrt_call_internal(struct hrt_call *entry, hrt_abstime deadline, hrt_abstime inte
 	irqstate_t flags = irqsave();
 
 	/* if the entry is currently queued, remove it */
-        /* note that we are using a potentially uninitialised
-           entry->link here, but it is safe as sq_rem() doesn't
-           dereference the passed node unless it is found in the
-           list. So we potentially waste a bit of time searching the
-           queue for the uninitialised entry->link but we don't do
-           anything actually unsafe.
-        */
+	/* note that we are using a potentially uninitialised
+	   entry->link here, but it is safe as sq_rem() doesn't
+	   dereference the passed node unless it is found in the
+	   list. So we potentially waste a bit of time searching the
+	   queue for the uninitialised entry->link but we don't do
+	   anything actually unsafe.
+	*/
 	if (entry->deadline != 0)
 		sq_rem(&entry->link, &callout_queue);
 
@@ -782,7 +803,7 @@ hrt_call_internal(struct hrt_call *entry, hrt_abstime deadline, hrt_abstime inte
 	irqrestore(flags);
 }
 
-/*
+/**
  * If this returns true, the call has been invoked and removed from the callout list.
  *
  * Always returns false for repeating callouts.
@@ -793,7 +814,7 @@ hrt_called(struct hrt_call *entry)
 	return (entry->deadline == 0);
 }
 
-/*
+/**
  * Remove the entry from the callout list.
  */
 void
@@ -876,17 +897,18 @@ hrt_call_invoke(void)
 		/* if the callout has a non-zero period, it has to be re-entered */
 		if (call->period != 0) {
 			// re-check call->deadline to allow for
-			// callouts to re-schedule themselves 
+			// callouts to re-schedule themselves
 			// using hrt_call_delay()
 			if (call->deadline <= now) {
 				call->deadline = deadline + call->period;
 			}
+
 			hrt_call_enter(call);
 		}
 	}
 }
 
-/*
+/**
  * Reschedule the next timer interrupt.
  *
  * This routine must be called with interrupts disabled.
diff --git a/src/modules/attitude_estimator_ekf/attitude_estimator_ekf_params.c b/src/modules/attitude_estimator_ekf/attitude_estimator_ekf_params.c
index 52dac652be..3cfddf28ed 100755
--- a/src/modules/attitude_estimator_ekf/attitude_estimator_ekf_params.c
+++ b/src/modules/attitude_estimator_ekf/attitude_estimator_ekf_params.c
@@ -52,11 +52,13 @@ PARAM_DEFINE_FLOAT(EKF_ATT_V3_Q3, 0.005f);
 PARAM_DEFINE_FLOAT(EKF_ATT_V3_Q4, 0.0f);
 
 /* gyro measurement noise */
-PARAM_DEFINE_FLOAT(EKF_ATT_V3_R0, 0.0008f);
-PARAM_DEFINE_FLOAT(EKF_ATT_V3_R1, 10000.0f);
-PARAM_DEFINE_FLOAT(EKF_ATT_V3_R2, 1.0f);
-/* accelerometer measurement noise */
-PARAM_DEFINE_FLOAT(EKF_ATT_V3_R3, 0.0f);
+PARAM_DEFINE_FLOAT(EKF_ATT_V4_R0, 0.0008f);
+/* accel measurement noise */
+PARAM_DEFINE_FLOAT(EKF_ATT_V4_R1, 10000.0f);
+/* mag measurement noise */
+PARAM_DEFINE_FLOAT(EKF_ATT_V4_R2, 100.0f);
+/* offset estimation - UNUSED */
+PARAM_DEFINE_FLOAT(EKF_ATT_V4_R3, 0.0f);
 
 /* offsets in roll, pitch and yaw of sensor plane and body */
 PARAM_DEFINE_FLOAT(ATT_ROLL_OFF3, 0.0f);
@@ -72,10 +74,10 @@ int parameters_init(struct attitude_estimator_ekf_param_handles *h)
 	h->q3 	=	param_find("EKF_ATT_V3_Q3");
 	h->q4 	=	param_find("EKF_ATT_V3_Q4");
 
-	h->r0 	=	param_find("EKF_ATT_V3_R0");
-	h->r1 	=	param_find("EKF_ATT_V3_R1");
-	h->r2 	=	param_find("EKF_ATT_V3_R2");
-	h->r3 	=	param_find("EKF_ATT_V3_R3");
+	h->r0 	=	param_find("EKF_ATT_V4_R0");
+	h->r1 	=	param_find("EKF_ATT_V4_R1");
+	h->r2 	=	param_find("EKF_ATT_V4_R2");
+	h->r3 	=	param_find("EKF_ATT_V4_R3");
 
 	h->roll_off  =	param_find("ATT_ROLL_OFF3");
 	h->pitch_off =	param_find("ATT_PITCH_OFF3");
diff --git a/src/modules/px4iofirmware/controls.c b/src/modules/px4iofirmware/controls.c
index f630b6f2a7..541eed0e1c 100644
--- a/src/modules/px4iofirmware/controls.c
+++ b/src/modules/px4iofirmware/controls.c
@@ -50,7 +50,7 @@
 #define RC_CHANNEL_HIGH_THRESH		5000
 #define RC_CHANNEL_LOW_THRESH		-5000
 
-static bool	ppm_input(uint16_t *values, uint16_t *num_values);
+static bool	ppm_input(uint16_t *values, uint16_t *num_values, uint16_t *frame_len);
 
 static perf_counter_t c_gather_dsm;
 static perf_counter_t c_gather_sbus;
@@ -94,7 +94,7 @@ controls_tick() {
 	 * other.  Don't do that.
 	 */
 
-	/* receive signal strenght indicator (RSSI). 0 = no connection, 1000: perfect connection */
+	/* receive signal strenght indicator (RSSI). 0 = no connection, 255: perfect connection */
 	uint16_t rssi = 0;
 
 	perf_begin(c_gather_dsm);
@@ -108,7 +108,7 @@ controls_tick() {
 		else
 			r_status_flags &= ~PX4IO_P_STATUS_FLAGS_RC_DSM11;
 
-		rssi = 1000;
+		rssi = 255;
 	}
 	perf_end(c_gather_dsm);
 
@@ -125,11 +125,11 @@ controls_tick() {
 	 * disable the PPM decoder completely if we have S.bus signal.
 	 */
 	perf_begin(c_gather_ppm);
-	bool ppm_updated = ppm_input(r_raw_rc_values, &r_raw_rc_count);
+	bool ppm_updated = ppm_input(r_raw_rc_values, &r_raw_rc_count, &r_page_status[PX4IO_P_STATUS_RC_DATA]);
 	if (ppm_updated) {
 
 		/* XXX sample RSSI properly here */
-		rssi = 1000;
+		rssi = 255;
 
 		r_status_flags |= PX4IO_P_STATUS_FLAGS_RC_PPM;
 	}
@@ -321,7 +321,7 @@ controls_tick() {
 }
 
 static bool
-ppm_input(uint16_t *values, uint16_t *num_values)
+ppm_input(uint16_t *values, uint16_t *num_values, uint16_t *frame_len)
 {
 	bool result = false;
 
@@ -345,6 +345,10 @@ ppm_input(uint16_t *values, uint16_t *num_values)
 		/* clear validity */
 		ppm_last_valid_decode = 0;
 
+		/* store PPM frame length */
+		if (num_values)
+			*frame_len = ppm_frame_length;
+
 		/* good if we got any channels */
 		result = (*num_values > 0);
 	}
diff --git a/src/modules/px4iofirmware/protocol.h b/src/modules/px4iofirmware/protocol.h
index c10f0167c4..e5bef6eb3a 100644
--- a/src/modules/px4iofirmware/protocol.h
+++ b/src/modules/px4iofirmware/protocol.h
@@ -128,7 +128,8 @@
 #define PX4IO_P_STATUS_VSERVO			6	/* [2] servo rail voltage in mV */
 #define PX4IO_P_STATUS_VRSSI			7	/* [2] RSSI voltage */
 #define PX4IO_P_STATUS_PRSSI			8	/* [2] RSSI PWM value */
-#define PX4IO_P_STATUS_NRSSI			9	/* [2] Normalized RSSI value, 0: no reception, 1000: perfect reception */
+#define PX4IO_P_STATUS_NRSSI			9	/* [2] Normalized RSSI value, 0: no reception, 255: perfect reception */
+#define PX4IO_P_STATUS_RC_DATA			10	/* [1] + [2] Details about the RC source (PPM frame length, Spektrum protocol type) */
 
 /* array of post-mix actuator outputs, -10000..10000 */
 #define PX4IO_PAGE_ACTUATORS		2		/* 0..CONFIG_ACTUATOR_COUNT-1 */
diff --git a/src/modules/px4iofirmware/registers.c b/src/modules/px4iofirmware/registers.c
index 916b893c45..0358725db3 100644
--- a/src/modules/px4iofirmware/registers.c
+++ b/src/modules/px4iofirmware/registers.c
@@ -89,7 +89,9 @@ uint16_t		r_page_status[] = {
 	[PX4IO_P_STATUS_IBATT]			= 0,
 	[PX4IO_P_STATUS_VSERVO]			= 0,
 	[PX4IO_P_STATUS_VRSSI]			= 0,
-	[PX4IO_P_STATUS_PRSSI]			= 0
+	[PX4IO_P_STATUS_PRSSI]			= 0,
+	[PX4IO_P_STATUS_NRSSI]			= 0,
+	[PX4IO_P_STATUS_RC_DATA]		= 0
 };
 
 /**
@@ -582,6 +584,7 @@ registers_set_one(uint8_t page, uint8_t offset, uint16_t value)
 			/* this option is normally set last */
 			if (value & PX4IO_P_RC_CONFIG_OPTIONS_ENABLED) {
 				uint8_t count = 0;
+				bool disabled = false;
 
 				/* assert min..center..max ordering */
 				if (conf[PX4IO_P_RC_CONFIG_MIN] < 500) {
@@ -600,7 +603,10 @@ registers_set_one(uint8_t page, uint8_t offset, uint16_t value)
 				if (conf[PX4IO_P_RC_CONFIG_DEADZONE] > 500) {
 					count++;
 				}
-				if (conf[PX4IO_P_RC_CONFIG_ASSIGNMENT] >= PX4IO_RC_MAPPED_CONTROL_CHANNELS) {
+
+				if (conf[PX4IO_P_RC_CONFIG_ASSIGNMENT] == UINT8_MAX) {
+					disabled = true;
+				} else if ((int)(conf[PX4IO_P_RC_CONFIG_ASSIGNMENT]) < 0 || conf[PX4IO_P_RC_CONFIG_ASSIGNMENT] >= PX4IO_RC_MAPPED_CONTROL_CHANNELS) {
 					count++;
 				}
 
@@ -608,7 +614,7 @@ registers_set_one(uint8_t page, uint8_t offset, uint16_t value)
 				if (count) {
 					isr_debug(0, "ERROR: %d config error(s) for RC%d.\n", count, (channel + 1));
 					r_status_flags &= ~PX4IO_P_STATUS_FLAGS_INIT_OK;
-				} else {
+				} else if (!disabled) {
 					conf[index] |= PX4IO_P_RC_CONFIG_OPTIONS_ENABLED;
 				}
 			}
diff --git a/src/modules/px4iofirmware/sbus.c b/src/modules/px4iofirmware/sbus.c
index 6aca2bd113..11ccd7356a 100644
--- a/src/modules/px4iofirmware/sbus.c
+++ b/src/modules/px4iofirmware/sbus.c
@@ -280,7 +280,7 @@ sbus_decode(hrt_abstime frame_time, uint16_t *values, uint16_t *num_values, uint
 		*rssi = 100; // XXX magic number indicating bad signal, but not a signal loss (yet)
 	}
 
-	*rssi = 1000;
+	*rssi = 255;
 
 	return true;
 }
diff --git a/src/modules/sensors/sensor_params.c b/src/modules/sensors/sensor_params.c
index c54128cb52..7637235548 100644
--- a/src/modules/sensors/sensor_params.c
+++ b/src/modules/sensors/sensor_params.c
@@ -104,49 +104,49 @@ PARAM_DEFINE_FLOAT(RC1_MIN, 1000.0f);
 PARAM_DEFINE_FLOAT(RC1_TRIM, 1500.0f);
 PARAM_DEFINE_FLOAT(RC1_MAX, 2000.0f);
 PARAM_DEFINE_FLOAT(RC1_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC1_DZ, 0.0f);
+PARAM_DEFINE_FLOAT(RC1_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC2_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC2_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC2_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC2_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC2_DZ, 0.0f);
+PARAM_DEFINE_FLOAT(RC2_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC3_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC3_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC3_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC3_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC3_DZ, 0.0f);
+PARAM_DEFINE_FLOAT(RC3_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC4_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC4_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC4_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC4_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC4_DZ, 30.0f);
+PARAM_DEFINE_FLOAT(RC4_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC5_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC5_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC5_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC5_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC5_DZ,  0.0f);
+PARAM_DEFINE_FLOAT(RC5_DZ,  10.0f);
 
 PARAM_DEFINE_FLOAT(RC6_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC6_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC6_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC6_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC6_DZ, 0.0f);
+PARAM_DEFINE_FLOAT(RC6_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC7_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC7_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC7_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC7_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC7_DZ, 0.0f);
+PARAM_DEFINE_FLOAT(RC7_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC8_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC8_TRIM, 1500);
 PARAM_DEFINE_FLOAT(RC8_MAX, 2000);
 PARAM_DEFINE_FLOAT(RC8_REV, 1.0f);
-PARAM_DEFINE_FLOAT(RC8_DZ, 0.0f);
+PARAM_DEFINE_FLOAT(RC8_DZ, 10.0f);
 
 PARAM_DEFINE_FLOAT(RC9_MIN, 1000);
 PARAM_DEFINE_FLOAT(RC9_TRIM, 1500);
diff --git a/src/modules/systemlib/ppm_decode.h b/src/modules/systemlib/ppm_decode.h
index 6c5e15345e..5a1ad84da9 100644
--- a/src/modules/systemlib/ppm_decode.h
+++ b/src/modules/systemlib/ppm_decode.h
@@ -57,6 +57,7 @@ __BEGIN_DECLS
  * PPM decoder state
  */
 __EXPORT extern uint16_t	ppm_buffer[PPM_MAX_CHANNELS];	/**< decoded PPM channel values */
+__EXPORT extern uint16_t	ppm_frame_length;				/**< length of the decoded PPM frame (includes gap) */
 __EXPORT extern unsigned	ppm_decoded_channels;	/**< count of decoded channels */
 __EXPORT extern hrt_abstime	ppm_last_valid_decode;	/**< timestamp of the last valid decode */